Discover ProtectBabyMonitor service providers on the network

Attempt to discover any providers of the ProtectBabyMonitor
service on the local network, resolving any which are found.
For now nothing is done with the information on found
providers.

src/protect/babymonitor/DiscoverActivity.java

@@ -17,6 +17,9 @@
 package protect.babymonitor;
 
 import android.app.Activity;
+import android.content.Context;
+import android.net.nsd.NsdManager;
+import android.net.nsd.NsdServiceInfo;
 import android.os.Bundle;
 import android.util.Log;
 
@@ -24,13 +27,21 @@ public class DiscoverActivity extends Activity
 {
     final String TAG = "BabyMonitor";
 
+    NsdManager _nsdManager;
+
+    NsdManager.DiscoveryListener _discoveryListener;
+
     @Override
     protected void onCreate(Bundle savedInstanceState)
     {
         Log.i(TAG, "Baby monitor start");
 
+        _nsdManager = (NsdManager)this.getSystemService(Context.NSD_SERVICE);
+
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_discover);
+
+        startServiceDiscovery("_babymonitor._tcp.");
     }
 
     @Override
@@ -38,6 +49,99 @@ public class DiscoverActivity extends Activity
     {
         Log.i(TAG, "Baby monitoring stop");
 
+        if(_discoveryListener != null)
+        {
+            Log.i(TAG, "Unregistering monitoring service");
+
+            _nsdManager.stopServiceDiscovery(_discoveryListener);
+            _discoveryListener = null;
+        }
+
         super.onDestroy();
     }
+
+    public void startServiceDiscovery(final String serviceType)
+    {
+        final NsdManager nsdManager = (NsdManager)this.getSystemService(Context.NSD_SERVICE);
+
+        // Instantiate a new DiscoveryListener
+        _discoveryListener = new NsdManager.DiscoveryListener()
+        {
+            //  Called as soon as service discovery begins.
+            @Override
+            public void onDiscoveryStarted(String regType)
+            {
+                Log.d(TAG, "Service discovery started");
+            }
+
+            @Override
+            public void onServiceFound(NsdServiceInfo service) {
+                // A service was found!  Do something with it.
+                Log.d(TAG, "Service discovery success: " + service);
+
+                if (!service.getServiceType().equals(serviceType))
+                {
+                    // Service type is the string containing the protocol and
+                    // transport layer for this service.
+                    Log.d(TAG, "Unknown Service Type: " + service.getServiceType());
+                }
+                else if (service.getServiceName().contains("ProtectBabyMonitor"))
+                {
+                    NsdManager.ResolveListener resolver = new NsdManager.ResolveListener()
+                    {
+                        @Override
+                        public void onResolveFailed(NsdServiceInfo serviceInfo, int errorCode)
+                        {
+                            // Called when the resolve fails.  Use the error code to debug.
+                            Log.e(TAG, "Resolve failed" + errorCode);
+                        }
+
+                        @Override
+                        public void onServiceResolved(final NsdServiceInfo serviceInfo)
+                        {
+                            Log.e(TAG, "Resolve Succeeded. " + serviceInfo);
+
+                        }
+                    };
+
+                    _nsdManager.resolveService(service, resolver);
+                }
+                else
+                {
+                    Log.d(TAG, "Unknown Service name: " + service.getServiceName());
+                }
+            }
+
+            @Override
+            public void onServiceLost(NsdServiceInfo service)
+            {
+                // When the network service is no longer available.
+                // Internal bookkeeping code goes here.
+                Log.e(TAG, "service lost" + service);
+            }
+
+            @Override
+            public void onDiscoveryStopped(String serviceType)
+            {
+                Log.i(TAG, "Discovery stopped: " + serviceType);
+            }
+
+            @Override
+            public void onStartDiscoveryFailed(String serviceType, int errorCode)
+            {
+                Log.e(TAG, "Discovery failed: Error code:" + errorCode);
+                nsdManager.stopServiceDiscovery(this);
+            }
+
+            @Override
+            public void onStopDiscoveryFailed(String serviceType, int errorCode)
+            {
+                Log.e(TAG, "Discovery failed: Error code:" + errorCode);
+                nsdManager.stopServiceDiscovery(this);
+            }
+        };
+
+        nsdManager.discoverServices(
+                serviceType, NsdManager.PROTOCOL_DNS_SD, _discoveryListener);
+    }
 }